1. Field of the Invention:
An improved rocker arm adjusting nut particularly suited for use with steel rocker arms, in automotive engines, in order to achieve an improved cooling and feed oil flow to the pivot ball-rocker arm interface.
2. Brief Description of the Prior Art:
Rocker arms commonly are used in an overhead valve, internal combustion engine to translate linear motion from a push rod to linear actuation of a poppet valve. Typically, such rocker arms are stamped steel, and are maintained in place by a rocker arm adjusting nut, whereby a frictional movement occurs between a pivot ball and an inner rocker arm surface. Representative prior art rocker arm and adjusting nut designs are shown by the prior U.S. patents, as follows:
HEDBERG: 1,469,155 PA1 O'HARROW: 2,288,831 PA1 THOMPSON: 3,251,350 PA1 AYRES: 3,875,908 PA1 CLANCY: 4,440,121 PA1 KIMURA et al.: 4,537,166 PA1 SHEEHAN: 4,655,176
In summary, these prior art references illustrate a variety of techniques for lubricating rocker arms and overhead valve internal combustion engines. For example, AYRES illustrates an oil deflector mounted on the pivoted end of a rocker arm, so as to direct oil being discharged from cam lobes into an aperture, of the rocker arm. In contrast, the present invention essentially involves improvement by an oil deflecting shoulder at the top of an extended rocker arm adjusting nut, wherein this shoulder and associated structure of the nut enhances lubrication of the rocker arm-pivot ball interface by redirecting oil downward, towards a fulcrum at that interface. The improved rocker arm adjusting nut herein also has a significantly increased mass, in order to function as a heat sink. An axially extended middle portion also defines a large, vertical surface that is channeled to direct oil downward to the pivot ball-rocker arm interface, for the purpose of improving lubrication and cooling at that critical zone.
The HEDBERG and O'HARROW rocker arms are of the shaft-mounted types and are noted simply for discussions of how oil is necessary to lubricate a bearing surface.
THOMPSON illustrates a rocker arm shaft mounting assembly wherein lands (34 FIG. 5) extend from a horizontally disposed shaft, in order to urge lubricant towards the needle bearing supporting the rocker arm on that shaft.
AYRES illustrates a cam-over-rocker type of valve gear arrangement for an internal combustion engine in which an oil deflector, 26, (FIG. 1) is mounted at the end of a rocker arm, so that oil discharged from a cam wil be deflected into an aperture of the rocker arm.
CLANCY et al. illustrate a nut lock device for an engine rocker arm adjustment, and shows a conventional rocker arm by oil ejected through lubricating passage 54. Oil pressurized by a hydraulic valve like 15 is sent through a hollow push rod, 24, and out operature 2421.
KIMURA et al. demonstrates another rocker arm shaft assembly with bolts that have annular flanges (34, 35 in FIG. 6) and enlarged portions to fit tightly against a seating member, to prevent leakage of oil from the hollow interior of a rocker shaft.
SHEEHAN shows a high-performance, shaft-mounted rocker arm of the solid aluminum variety, that categorically is not subject to the lubrication and cooling failures of conventional, stamped steel rocker arms mounted on pivot balls, as found in many production engines manufactured in the United States.
The present invention is distinguished from such prior art by a rocker arm adjusting nut, with a locking screw, that is capable of use with stamped steel rockers and rocker adjusting ball pivots to improve lubrication and heat dissipation without further modification of the rocker arm or the pivot ball. The present invention not only directs engine oil to lubricate the highly stressed pivot ball-rocker arm interface, but the nut also reduces heat build-up by conducting heat away from that same critical area.
Accordingly, a first object of the present invention is to provide a rocker arm adjusting nut that will catch and redirect lubricating oil droplets in a controlled fashion to the pivot ball-rocker arm interface, to enhance lubrication of that high friction area.
A second objection of the present invention is to provide a rocker arm adjusting nut that is capable of interacting with a rocker arm of the conventional stamped steel variety, without requiring any modification of the rocker arm or any associated valve train element.
A third object of the present invention is to define an improved rocker arm adjusting nut that will enhance heat transfer away from the pivot ball-rocker arm interface so as to prevent burning of pivot balls and to increase rocker arm life.
The present invention is characterized by an overall novel cooperation of structure that achieves each of the above-described objects. Simple replacement of the rocker arm adjustment nut has been found to achieve longer life for a stamped steel rocker arm, by eliminating the common problems of oil starvation to the pivot ball and burning of the pivot ball due to localized high temperatures.